1. Field of the Invention
The present invention relates generally to a system and apparatus for protecting equipment associated with oil and gas producing wells and, more specifically, for protecting exposed well head equipment such as Christmas trees, valves and accessory equipment located at the well surface.
2. Description of the Prior Art
The nature of the ordinary well head is such that it embodies sufficient control means that the well can be adjusted to safely produce at a desired rate. Depending on the type of formation being produced and other factors, the well head itself can assume different proportions and embody varying forms of equipment adapted to the particular conditions at hand. It is customary in the oil and gas industry to refer to the upper most portion of the well head as it leaves the surface of the ground as the “Christmas tree.” The Christmas tree is generally an assembly of valves, tees, crosses, and other fittings at the well head used to control oil or gas production and to give access to the well tubing. Other fittings such as choke jackets, pressure gauges, and the like, can become part of what is known in the art as the “Christmas tree.” Many times, a master valve is provided on the Christmas tree which controls the flow of gas or oil directly from the well itself. This valve can be closed, preventing any flow from the well to the Christmas tree itself.
Other valuable devices, such as additional expensive valves, may also be present at the well head. Many times, a very expensive control valve may be mounted on a pipeline itself. These valves and controllers are quite expensive, and their damage likewise brings a loss of production or supply of oil or gas flowing with the pipeline. While this assembly of valves, tees and other fittings which is affixed to the gas well or oil well at the well head is fairly sturdy in construction, it is possible for it to become damaged in a number of different situations.
One way in which damage can occur is due to the nature of the proximity of plural wells being completed within feet of each other. Often, where a highly productive oil or gas reserve field is discovered, a number of wells will be drilled into the area, each being furnished with a well head which protrudes just above the ground. Often in a highly productive area, these well heads are closely spaced. This situation creates particular concern where a new well is being completed in close proximity to an already completed well head or well heads. It is always possible that equipment can be dropped on the existing well head/heads, for example, by a crane being used to move a new Christmas tree into position at the site. The undesirable consequence of such damage could be an uncontrolled flow of the crude oil or gas. There have been instances, for example, where well heads have been damaged to the point of requiring replacement of one or more of the component parts.
Various schemes have been proposed for protecting both surface well head equipment and also sub-sea well head equipment. However, the prior art proposals have generally been lacking in one or more respects. For example, certain of the prior art constructions were permanent in nature and were not easily removed or transported from one well site to another.
A further feature of a suitable well head protective enclosure for the present purposes is that it must accommodate workover tools and instruments which are periodically inserted into the well for various reasons. It is also obviously necessary for worker personnel to be able to access the well head components to perform these and other customary operations. The protective enclosure must not impede these necessary operations.
It has therefore become a desirable to provide some form of protective enclosure for a well head of the type under consideration, especially where several well heads are located in close proximity. Preferably, the protective structure would be designed to deflect or deter damaging contact between a well head and heavy moving objects or lines. A primary function of the protective enclosure would be to permit the well head to operate in a safe manner and yet be readily accessible for workover purposes and/or for inspection, routine maintenance, or other such purposes. The enclosure would also preferably be assembled from a number of component parts which could be disassembled and transported to another location, when desired, with a minimum of effort being required for the disassembly.
Thus, despite the advances which have been made in well head construction, there continues to exist a need for an improved well head enclosure which would meet the previously expressed needs.